Notes from the Lab: Polly Molt Watch 2020!

In case you missed yesterday’s Online Bug Encounter, we have a very special update on everyone’s favorite Bug Ambassador! Polly, our Goliath Birdeating Tarantula, successfully molted on Saturday afternoon!

Could there be a more fitting way to wrap up not only our arachnid-filled April but our Missoula Gives campaign? Polly’s timing could not have been more perfect.

In actuality, we knew that Polly would be molting soon; she’d been in a state of “pre-molt” for a while now. She stopped eating several months ago, and in the meantime began excavating her burrow until it became so deep she dug right through to the other side of her enclosure. Tarantulas don’t exactly have “digging claws,” so in order to remove dirt from her burrow, she would lay down some silk, then use her pedipalps to gather it into a ball, and physically carry it out of her burrow and drop it near the entrance.

January 2020: Polly’s great excavation begins!

Polly’s work didn’t end there. When her burrow was to her liking, she walled up the entrance with silk. Up until this point, we were still attempting to feed her (just in case) but this was a clear sign that she did NOT want to be disturbed.

No solicitors, please.

Once she had walled herself off to the outside world, it was time to play the waiting game. This was back in February. We would check on her every day, but she hardly moved for months. Then, about a week ago, she gave us a few more clues about her impending molt.

Patiently waiting.

Polly began kicking off her urticating hairs. She would kick them off in huge tufts, coating the inside of the burrow and absolutely covering herself. Tarantulas are extremely vulnerable and defenseless during a molt, and if a predator came sniffing along, they would be deterred by a nose or mouthful of loose urticating hairs.

A recuperating tarantula.

Then, on May 1st, Polly finally molted! The molting process took several hours, and it may be a few more weeks before she emerges from her burrow. In the meantime, she is resting up, and waiting for her exoskeleton to harden. The flash of red you see in the photo above are her fangs, still undergoing a process called sclerotization; it may take several days for them to sclerotize, or harden, but they will be black when they finally do.